Merge pull request #118 from blueimp/docker

Optimise the Dockerfile for Docker Hub Automated Builds.

.dockerignore

@@ -0,0 +1 @@
+*

Dockerfile

@@ -1,7 +1,34 @@
-FROM golang:1.4
+#
+# MailHog Dockerfile
+#
 
-RUN go get github.com/mailhog/MailHog
+FROM alpine:3.4
 
-EXPOSE 1025 8025
+# Install ca-certificates, required for the "release message" feature:
+RUN apk --no-cache add \
+    ca-certificates
+
+# Install MailHog:
+RUN apk --no-cache add --virtual build-dependencies \
+    go \
+    git \
+  && mkdir -p /root/gocode \
+  && export GOPATH=/root/gocode \
+  && go get github.com/mailhog/MailHog \
+  && mv /root/gocode/bin/MailHog /usr/local/bin \
+  && rm -rf /root/gocode \
+  && apk del --purge build-dependencies
+
+# Add mailhog user/group with uid/gid 1000.
+# This is a workaround for boot2docker issue #581, see
+# https://github.com/boot2docker/boot2docker/issues/581
+RUN adduser -D -u 1000 mailhog
+
+USER mailhog
 
-ENTRYPOINT ["/go/bin/MailHog"]
+WORKDIR /home/mailhog
+
+ENTRYPOINT ["MailHog"]
+
+# Expose the SMTP and HTTP ports:
+EXPOSE 1025 8025